The present invention relates to soldering and desoldering tools and methods.
Various tools and techniques have been developed to attempt to quickly and easily desolder chips and components from circuit boards. Examples of these devices are shown in U.S. Pat. Nos. 4,274,576; 4,136,444; 4,066,204; 3,990,863; 3,766,623; 3,649,809; 3,746,239; 3,632,973; 3,643,036; 3,582,610; 3,576,969; 3,552,630; 3,050,612; 3,407,985; and 2,293,455.
A review of these patents indicates that the bulk of the prior teachings go to desoldering DIP chips. For example U.S. Pat. Nos. 3,632,073; 3,990,863; and 4,136,444 show desoldering methods for DIP chips wherein heat is directly applied to the DIP chip pins while an associated mechanism grasps the chip and extracts it from the board. U.S. Pat. Nos. 3,632,036; 3,746,239; 3,649,809; and 3,766,036 show tools for heating the pins of a DIP chip to melt the solder joints. U.S. Pat. Nos. 3,746,239; 3,649,809; and 3,766,623; on the other hand, show tools for heating the DIP solder joints directly at the circuit board. None of the prior art devices disclose or suggest a tool or method for desoldering a leadless type chip. A "leadless chip" is a chip having input/output sockets rather than input/output pins. Such a chip is believed to have been first disclosed in the commonly assigned copending patent application of Warren B. Marquardt, Ser. No. 396,539, filing date July 8, 1982, entitled "Improved Chip/Circuit Board Interface Structure and Method."
It is characteristic of leadless chips to have a "high pin count." That is, a high number of pin/socket solder connections per chip. Typically in excess of 100 such solder connections are required to solder a leadless chip to a corresponding array of pins. The need for desoldering tools for high pin count chips is especially great. There is apparently relatively little prior art showing soldering, as opposed to desoldering, tools and methods. U.S. Pat. No. 3,576,969 shows one tool for soldering a multilead chip. The tool would be unsuitable, however, for a leadless-type chip.
There is consequently a need for quick, simple and safe soldering as well as desoldering tools and methods for leadless chips.